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Aeroelastic response of helicopter rotor blade with dynamic wake modeling
V. Lokeswara Rao, M.R. Kumar,
Published in American Helicopter Society International
A helicopter rotor is probably the most complex aeroelastic system. The aeroelastic response problem of a complete rotor involves the blade degrees of freedom and unsteady aerodynamics with three-dimensional effects. The aeroelastic response problem that manifests itself as blade loads, hub loads, or fuselage vibrations has a critical role for rotary-wing vehicles. Aeroelastic response analysis of helicopter rotor requires the development of multidisciplinary comprehensive analysis program which combines structure, aerodynamic and inertial operators. In this study, one such comprehensive analysis model is described. The model includes elastic flap-lag-torsion and axial blade deformations, modified ONERA dynamic stall theory for airloads calculation, and Peters-He dynamic wake theory for inflow computation. In the present study the number of state variables representing the inflow is varied from 3 states to 45 states by increasing the number of harmonics and radial functions, and their effects on helicopter trim, rotor loads and control response are analyzed. Results indicate that there is a clear redistribution of inflow with the increase in number of inflow states. In general there is an increase in the inflow from forward to the aft of the rotor disk with the increase in number of states. It is important to note that there is no significant change in the trim variables with the increase in number of inflow states. However with the inclusion of higher harmonic inflow states, the harmonic contents increase in sectional loads and blade root loads. Higher inflow states are seen to affect helicopter control response to longitudinal input at high speeds. © 2015 by the Asian-Australian Rotorcraft Forum. All rights reserved.
About the journal
JournalARF 2015 - 4th Asian-Australian Rotorcraft Forum
PublisherAmerican Helicopter Society International